As is known, self-breakable ampoules are glass ampoules comprising a pre-breaking line in the vicinity of at least one of their ends in a neck zone having a smaller diameter than that of the body of the ampoule, so that the user can break the ampoule without a file by exerting simple lateral pressure on the ampoule with his fingers on either side of the prebreaking line. This prebreaking line can be obtained by numerous processes, such as filing, localized enamelling of the glass, localized heating or the like.
The diameter at the prebreaking line is limited by the possibility of breaking the ampoule manually. In practice, this diameter cannot exceed approximately 8 mm. Under these conditions, it is not possible to obtain an opening allowing for the free flow of the product as in the case of a bottle. Consequently, the flow of the liquid product contained in the ampoules is often a problem and the user has to shake the ampoule vigorously in order to empty it.
In order to improve the flow of the product, it is known to open the ampoule at both ends. However, this process limits the shapes that can be used for the ampoule as the ampoule must comprise two necks or two tips. In addition, the entire dose of product contained in the ampoule must all be used at once.
It has also been proposed to slip a small dispensing nipple of flexible material over the neck zone after breakage, this nipple having the shape of the finger of a glove and being provided at its end with a .small dispensing orifice. By pressing repeatedly on this nipple, it serves as a pump and allows for dispensing of the product. However, this nipple is relatively expensive and the boxes of ampoules therefore comprise only one single nipple. This can be lost easily and the product contained in the remaining ampoules can then no longer be dispensed in a simple manner.
It is therefore desired to produce self-breakable ampoules of the "bottle" type which are opened at only one end, so that they can be given many different shapes, and from which the product can still flow freely, so that the entire dose contained in the ampoule does not all have to be used at once. Moreover, it is desired to avoid the addition of a nipple once the ampoule has been opened.
Moreover, it is known from FR-A 2 512 784 to apply a polymer covering having a thickness of several tenths of a millimeter to the prebreaking line by spraying or coating, in order to prevent the user from being injured by any glass splinters produced when the ampoule is broken. However, a covering of this kind applied only over the prebreaking ring does not allow for any improvement in the dispensing of the liquid product contained in the ampoule.